I've noticed a few posts that presumably contain the same content in both English and a secondary language (most frequently Spanish).
Sometimes the English translations are contributed by the OP in the original revision:
Occasionally a translation of the original post is later added:
In the last example, I'm not sure whether the question was closed due to its original lack of English content or due to its lack of a real question. (Note that I'm not asking how we should handle (monolingual) non-English content in general; I merely linked this question because it fits the multilingual pattern.)
If Stack Exchange's official language is English, should the non-English content of such posts be removed via edits, or is the multilingual content acceptable so long as English is represented in parallel?